Liquid/vapor absorption systems using ammonia refrigerant, often referred to as aqua-ammonia systems, are well-known in the art. These systems utilize absorber heat exchange or generator/absorber heat exchange (GAX) cycles carried out in absorption refrigeration chillers for supplying cooling, typically in the form of a chilled water supply directed to a hydronic loop cooperating with an indoor coil and other heat exchange components for transferring the cooling effect to the space to be conditioned. The basic components of such a chiller apparatus include an absorber, generator, condenser and evaporator and necessary piping for the ammonia refrigerant and the water-based absorption fluid. The heat to the generator is supplied by a burner, and a circulating pump is required for directing the absorption fluid through the apparatus components. When heating for the conditioned space is required, a separate water heater and tank or a furnace are used. Where the cooling and heating functions are combined in a chiller/heater assembly, two separate burners are used, one for cooling and one for the heating, and separate pumps are required for the two different hydronic loop functions.
In the aforesaid co-pending parent application, there is disclosed an improved and simplified aqua-ammonia absorption apparatus in which the cooling and heating functions are integrated into a single apparatus requiring only one burner for heating the generator and one solution pump for directing absorption fluid through the apparatus. The basic apparatus components are an absorber, a generator, condenser, a heat exchanger capable of functioning as both a condenser and an evaporator, and refrigerant by-pass conduit and valving to provide selective by-pass of the refrigerant from the generator to the heat exchanger without passing through the condenser. In the cooling mode or function, the heat exchanger functions as an evaporator. During a heating mode, the refrigerant from the generator by-passes the condenser and is directed to the heat exchanger which functions as the condenser to provide heat which is recovered for heating a conditioned space, water heating, etc. The aforesaid co-pending application, including the description of the apparatus and its operation, is incorporated herein by reference.
The present application is directed to a chiller/heater absorption apparatus in which refrigerant from the heat exchanger operating as a condenser in a heater mode of operation by-passes the absorber and is pumped to the generator, improving the heating efficiency of the system by reducing heat loss of the refrigerant to the absorber. In one embodiment using separate generator and rectifier columns, an aspirator device is used to direct a mixture of refrigerant and absorption solution from the rectifier column to the generator column in a chiller mode.